Soot blower for steam boilers



Oct.3, 1967 W.JANKOWSKI 3,344,459

SOOT BLOWER FOR STEAM BOILERS Filed April 16, .1965 2 Sheds-Sheet 1 Fig.1

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SOOT BLOWER FOR STEAM BOILERS Filed April 16, .1965 ZYSheets-Sheet z Fig. 3 8 @QX! I IN VEN TOR.

Af/ammys United States Patent 3,344,459 SOOT BLOWER FOR STEAM BOILERS Walter .l'ankowski, Essen-Katernherg, Germany, assignor to M. Spuhr & Co., Essen (Ruhr), Germany Filed Apr. 16, 1965, Ser. No. 448,746 4 Claims. (Cl. 15317) ABSTRACT OF Tit-IE DISCLOSURE A soot blower for a boiler has a pipe with a fluid discharge outlet which is introduced into a boiler through an opening in the wall. As the fluid is discharged inside the boiler it is directed at that Wall. The discharge outlet is rotated through 360 and continually advanced farther into the boiler so that the fluid describes a spiral pattern on the wall of the boiler. A control valve is coupled to this apparatus so that as the fluid outlet gets farther and farther into the boiler the fluid supply is gradually increased and as the nozzle is withdrawn towards the wall the fluid supply is gradually decreased. This valve comprises a sliding sleeve threaded into a fixed sleeve and overlying a hole in the pipe wall. All of these are enclosed in the pressure cylinder. As the pipe is moved farther and farther in the furnace the control sleeve is rotated so as to uncover more of the hole in the pipe wall.

The present invention relates to a soot blower for steam boilers, and more particularly a soot blower comprising a rotating blast pipe provided with a lateral blast nozzle which is insertable through the boiler shell, whereby a medium under pressure is blown against internal portions of the boiler wall. Soot blowers are known wherein removal of soot deposit is effected by blasting by means of air, steam or water under pressure. The jet of the pressure medium issuing laterally from the blast nozzle during rotation of the blast pipe impinges upon the boiler wall on a spiral path if the blast pipe during rotation thereof is simultaneously slowly advanced towards the boiler interior by an axial feeding device. A disadvantage of prior art soot blowers of this type resides in the fact that those portions of the internal boiler wall, commonly provided with steam pipes, next adjacent to the blast pipe are more strongly subjected to the jet of pressure medium than the remoter portions of the internal boiler wall. The irregular impingement on the boiler wall portions is of particular disadvantage if the soot deposit shall be removed by a water jet which may not exceed a specific force so as to avoid a thermal shock. However, also when blasting by means of air or steam under pressure, the nonuniform effect of the jet of pressure medium is apparently disadvantageous.

It is an object of the present invention to eliminate this disadvantage by avoiding different impingement upon adjacent and remoter boiler wall portions when blasting with a water jet.

This object is accomplished in accordance with the present invention by providing that the supply of pressure medium to the blast pipe is controllable by the feeding device such that it automatically increases with increasing advance. Thus, if the supply of pressure medium is made dependent on the respective position of the blast nozzle, a uniform impingement of pressure medium on a relatively large area of the internal boiler wall can be achieved during the advancing movement of the nozzle.

The invention may be particularly advantageously realized in that a connection pipe of the blast pipe, having a blind-end bore and a triangular control opening, is rotatably supported in a pressure medium cylinder mounted on the feeding device and is driven by a motor via the feed gear mechanism. A control sleeve initially covering the control opening is sealingly guided on the connection pipe, and this control sleeve, by means of a threaded portion thereon, is screwed during rotary movement of the connection pipe into an internally threaded sleeve fixedly secured in the pressure medium cylinder, thereby sliding relative to the connection pipe and increasingly releasing with the control edge thereof the passage through the triangular control opening so that the pressure medium from the pressure medium cylinder may enter through the control opening into the blind-end bore and the blast pipe.

An embodiment of the present invention is presented with reference to FIGS. 1 to 4 and described as follows:

FIG. 1 schematically illustrates the arrangement of the soot blower on the boiler shell.

FIG. 2 is an enlarged section of the pressure medium cylinder in connection with the drive.

FIG. 3 is a detail view of the feeding device.

FIG. 4 is an illustration of the spiral paths impinged upon during advance and return movements of the soot blower.

A boiler shell 1 has arranged thereinfront a guide rail 2 on which a carriage 3 is moving. A platform 3' of carriage 3 has mounted thereon a gear mechanism 4 and an electromotor 5 connected therewith. The electromotor 5, via a worm-wheel drive 4' of gear mechanism 4 and a pair of chain sprockets 7 loosely arranged on the rear axle 6 of carriage 3, drives a pair of chain sprockets 9, 9 on the front axle 8 thereof with strong reduction. In doing so, the smaller sprocket 9 connected with sprocket 9 engages, as is illustrated in FIG. 3, a chain 2 fixed on the guide rail 2 and rides thereon so that the carriage 3 slowly advances on the guide rail 2 towards the boiler shell 1. The platform 3' of carriage 3 has mounted thereon a pressure medium cylinder 11 connected to a flexible pressure medium line 10. A connection pipe 12 is rotatably supported in the pressure medium cylinder and rigidly connected with an output shaft 13 of the gear mechanism 4. The connection pipe 12 is in tightly threaded engagement with a blast pipe 14 having a lateral blast nozzle 15. During advance movement of carriage 3 the rotating blast pipe 14 will enter through an opening 16 of the boiler shell 1. A jet of pressure medium 17 issuing from the blast nozzle 15 blows against the sooted inside surface of the boiler shell 1 and initially impinges thereupon a short distance from opening 16. Upon further advance movement of carriage 3 the jet of pressure medium as is indicated as at 17. impinges upon the boiler wall 1 at a greater distance. Due to the rotation of the blast pipe 14 with simultaneous slow advance movement of carriage 3 the jet of pressure medium 17 describes a spiral circumferentially of the opening 16, blasting as at a being substantially more intensive than in the more outward area as at b.

To achieve a uniform blasting effect at a and b, provision is made in a manner such that the jet of pressure medium is weakest as at 17 and constantly increases until it reaches its full force as at 17', to be described in greater detail next.

As can be seen in FIG. 2, and to this end, the connection pipe 12 has provided therein a blind-end bore 18 being communicated with the pressure medium chamber 20 of cylinder 11 through a triangular control opening 19. Initially, this control opening 19 is completely covered by a control sleeve 21 sealingly slidable as at 22 on the connection pipe 12. With a threaded portion 23 thereof the control sleeve 21 is screwed into an internally threaded sleeve 24 and sealed with respect to the same by a sealing ring 25. Sleeve 24 is fixedly mounted in the pressure medium cylinder 11. Now, upon rotation of the connection pipe 12 effected through the output shaft 13 of gear mechanism 4 together with the described advance drive of carriage 3, the control sleeve 21 is being screwed into the fixed sleeve 24 and in doing so slides on connection pipe 12. The transmission ratios are adjusted such that the control edge 26 of control sleeve 21 will have just reached the forward point of the control opening 19 after having covered a dead distance, when by the advance movement of carriage 3 the nozzle 15 of blast pipe 14 has been guided through the boiler shell 1 and has been placed into operating position. Now, the control edge 26 commences to expose increasing frontal portions of the control opening 19 to chamber 20 so that pressure medium from chamber 20 may now pass into the connection pipe 12 and the blast pipe 14. Whereas initially the jet of pressure medium 17 issuing from nozzle 15 is relatively weak due to the initially small exposed cross-sectional area of the control opening 19, this jet will increase with every rotation of control sleeve 21 such that a constantly enlarging cross-sectional area of the control opening 19 will be opened. When the control sleeve 21 has reached its end position, the fullcross-section of the control opening 19 has been released, and also the blast pipe 14 will have advanced to its innermost end position by the forward movement of carriage 3, at which end position the maximum force of pressure medium 17 is available for blasting the area b of the boiler wall 1.

A limit switch (not shown) is effective in the end positions of carriage 3 to reverse the direction of rotation of drive motor so that the direction of rotation of the blast pipe 14 is reversed and the carriage 3 will move in the opposite direction. When this happens, the jet of pressure medium (17, 17) issuing from the blast nozzle during advance and return movements of carriage '3 would impinge upon the boiler wall 1 on the same spiral path. To avoid this and still improve on the effectiveness of the soot blower, as is shown in FIG. 3, the pair of chain sprockets 9, 9' are not fixedly connected to the front axle 8 of carriage 3, but are loosely mounted thereon. Hub 9" of the pair of chain sprockets 9, 9' has mounted therein a radial coupling pin 27 engaging a recess 23 extending through 180 of the front axle 8. With each change in the direction of rotation the pair of chain sprockets 9, 9' execute a half-turn before the front axle 8 is taken along by the coupling pin 27 and the carriage 3 is moved. During this idling half-tum of the pair of chain sprockets 9, 9'with carriage 3 standing stationarythe blast pipe 14 with the selection of suitable transmission ratios has already executed a half-turn. The result of this is that the jet of pressure medium 17, 17' during the advance and return movements of carriage 3 impinges upon the boiler wall 1 on two different spiral paths, indicated in FIG. 4 in the solid line showing as at 29, and in the broken line showing as at 30. Of course, this advance rotary movement of the blast pipe 14 with the carriage stationary may also be realized differently. For instance, instead of a single drive motor 5, two drive motors with one gear mechanism each may be provided of which one serves for rotating the blast pipe 14 and the other for advancing the carriage 3. In the end positions of carriage 3 limit switches are effective to reverse the direction of rotation of both motors, wherein the switching device may be designed such that the motor of the advancing drive is switched on with a certain delay with respect to the motor for effecting rotation, this delay corresponding to a rotation of the blast pipe 14.

The invention is claimed as follows:

1. In a soot blower for steam boilers wherein a blast pipe member having an angularly positioned fluid outlet communicating with an axial passageway in the blast pipe member is connected to a power means which axially advances the outlet end of the pipe in the furnace while rotating the pipe member so that the discharged fluid describes a spiral path on the furnace wall, the improvement comprising: valve means connected to said pipe member to control the flow of fluid going to said outlet and connected to the power means to be actuated thereby, to throttle the fluid flow when said outlet is closest to the wall, to have the fluid fiow substantially unthrottled when said outlet is farthest from the wall, and to gradually change the throttling between those two extremes.

2. In a soot blower as set forth in claim 1, including a stationary pressure cylinder surrounding a portion of the blast pipe member externally of the boiler, said cylinder forming a closed chamber about that portion of the pipe member, said valve means including a control sleeve member fitting closely to the wall of the pipe member in the chamber, said control sleeve member being moveable axially with respect to the pipe member, one of said members having an opening therethrough which opening is positioned to be substantially covered by the other member when the outlet is about at the wall and to be gradually uncovered as the power means moves the outlet farther into the boiler.

3. In a blower as set forth in claim 2, wherein said valve means includes an internally threaded sleeve secured to said cylinder and extending from the cylinder axially about the pipe member, said control sleeve member being externally threadml and being positioned between the ipe member and the fixed sleeve with its threads engaging the threads of the fixed sleeve, said control sleeve member being coupled to said pipe member to be rotated thereby, whereby the rotation of the pipe member causes the control sleeve member to change position axially along the pipe member.

4. In a blower as set forth in claim 3, wherein said pipe member is the one having said opening therein and said opening is triangular.

FOREIGN PATENTS 565,110 10/1944 Great Britain. 1,118,387 11/1961 Germany.

RQBERT W. MICHELL, Primary Examiner. 

1. IN A SOOT BLOWER FOR STEAM BOILERS WHEREIN A BLAST PIPE MEMBER HAVING AN ANGULARLY POSITIONED FLUID OUTLET COMMUNICATING WITH AN AXIAL PASSAGEWAY IN THE BLAST PIPE MEMBER IS CONNECTED TO A POWER MEANS WHICH AXIALLY ADVANCES THE OUTLET END OF THE PIPE IN THE FURNACE WHILE ROTATING THE PIPE MEMBER SO THAT THE DISCHARGED FLUID DESCRIBES A SPIRAL PATH ON THE FURNACE WALL, THE IMPROVEMENT COMPRISING: VALVE MEANS CONNECTED TO SAID PIPE MEMBER TO CONTROL THE FLOW OF FLUID GOING TO SAID OUTLET AND CONNECTED TO THE POWER MEANS TO BE ACTUATED THEREBY, TO THROTTLE THE FLUID FLOW WHEN SAID OUTLET IS CLOSEST TO THE WALL, TO HAVE THE FLUID FLOW SUBSTANTIALLY UNTHROTTLED WHEN SAID OUTLET IS FARTHEST FROM THE WALL, AND TO GRADUALLY CHANGE THE THROTTLING BETWEEN THOSE TWO EXTREMES. 